The present invention relates generally to the field of optical communications systems. More specifically, the present invention discloses a dispersion compensated optical wavelength router.
Wavelength division multiplexing is a commonly used technique that allows the transport of multiple optical signals, each at a slightly different wavelength, over an optical fiber. The ability to carry multiple signals on a single fiber allows that fiber to carry a tremendous amount of traffic, including data, voice, and digital video signals. For example, the International Telecommunications Union (ITU) Draft Recommendation G.mcs proposes a frequency grid which specifies various channel spacings including 100 GHz and 200 GHz. It would be advantageous to obtain smaller channel spacings. As transmission systems evolve to longer distances, smaller channel spacings, and higher bit rates, however, the phenomenon of dispersion becomes a limiting factor.
One embodiment of the present invention is an optical wavelength router that includes a beamsplitter, a first resonator, and a second resonator. The beamsplitter separate an input signal into a first beam and a second beam. The first resonator has a first center wavelength and reflects the first beam. The second resonator has a second center wavelength and reflects the second beam. The second center wavelength is offset relative to the first center wavelength by approximately one half of the free spectral range of the first resonator such that the resonance frequencies of the second resonator are matched to the anti-resonance frequencies of the first resonator.
The following technical advantages may be achieved by some, none, or all of the embodiments of the present invention. The optical wavelength router performs a multiplexing and/or a demultiplexing function to generate output waveforms that have a flat-top passband, good isolation, and very low chromatic dispersion.
These and other advantages, features, and objects of the present invention will be more readily understood in view of the following detailed description and the drawings.